High-tension insulator.



A. O..-AUSTIN.

HIGH TENISION INSULATOR. arnicmou nuzu MAY 19. 1913,

Patented July 17, 1917.

Z'SHEETS-SHEET l A. 0. AUSTIN.

HIGH TENSION INSULATOR.

APPLICATION man v19. ma.

Patented July 1?, 1917.

W44; z m/W UNITED STATES PATENT OFFICE.

ARTHUR O. AUSTIN, OF BABBERTON, OHIO, ASSIGNOR TO OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

HIGH-TENSION INSULATOB.

Barberton, county of Summit, and State of Ohio, have invented certain new and useful Improvements in High-Tension Insulators,

of which the following is a true, clear, and

exact specification.

My invention relates to electrical insulators and has more particular reference to improvementsin high tension insulators of the suspension or pin type.

The primary object of my invention is to provide an im roved high tension insulator which will e ectively withstand the de structive or damagin effects of lightning heav power arcs an such other abnormal conditions, and, in this connection my purpose is to cause the li htning flashovers or other abnormal distur ances to take place before the insulator becomes strained to the fracturing or puncturing point thereby relieving the insulation of such abnormal strains as would otherwise damage it.

A further object of my inventlon is to provide an improved insulator of such construction and'proportions as will cause flash overs or other disturbances to occur beyond or away from the insulator sufiiciently to prevent fracture or puncture of the members or parts of the insulator.

Other objects of my invention will appear hereinafter.

My invention consists in the features of novelty exemplified in the construction, combination, arrangement and proportions of parts herein described, and shown in the ac-- companying drawings which illustrate one embodiment of my invention, and more particularly pointed out in the appended claims.

In the drawings Figure 1 is a view of a complete suspension type high tension insulator embodying my invention.

Fig. 2 is a transverse central section of one of the unit disks or members thereof.

Fig. 3 is a view of a modified unit disk or member embodying my invention, the view being quarter-sectioned to better show the construction, and

Figs. 4: and 5 are views in elevation of still other modified unit disk members embodying my invention.

Whenever a high tension system of electrical distribution is subjected to a light- Specification of Letters Patent.

Patented Jul 17, 1917.

Appflcatlon filed May 19, 1913. Serial No 768,443.

ning charge or other similar condition, an abnormal rise in potential occurs which generally exists for a short period of time. This period of time is relatively too short to break down the air path between the conductor and the grounded insulator supports, and in consequence the insulators are directly subjected to this abnormal potential. Generally the potential to which the insulators are thus subjected is very much higher than that which would flashover if it existed for a relatively longer period of time or were applied at a low frequency. As a result of these conditions therefore the insulators break down by being punctured or fractured under the abnormal strains imposed thereon, and it is my purpose to safeguard the insulators against being subjected to such abnormal strains as cause them to break down.

In accordance with the principles involved in my invention I construct the insulator and proportion its parts in such manner that the air path between the conductor and the grounded insulator support will break down and the flashover occur outside of the insulator before the insulator becomes strained to the puncturing point; that is, the flashover will take place at less potential than that necessary to puncture the insulator. In order that my invention may be clearly understood I have embodied it in a high tension insulator of the suspension type but it will be obvious to one skilled in the art, after having obtained an under standing of my invention from the dis closures herein made, that my invention may be embodied in other types of insulators, such as the pin type, without departing from the scope and spirit of the invention.

The structure shown in the drawings is made up of three so-called insulator disks or unit members A, B and C linked together one above the other and the whole group suspended from the arm of a tower indicated by D in the drawings. At the lower end of the group a high tension electrical. conductor E is suspended. The disks are usually made of refractory material such as porcelain or other substances of high electrical insulating qualities-in the form of a shallow, inverted dish. An integral centrally disposed head or column 1 rises from the convex side of the dish and fits within a hollow inverted cap 2 (Figs. 2 and 3). This cap is usually made of metal for the purpose of strength and the cap and head 1 are held together in compact relation by means of a quantity of cement 3 placed between the adjacent inner and outer grooved faces of the cap and head, respectively. In the structure shown each cap has a slotted socket I which receiies the ball head 5 of a metallic bolt or pin 6 depending from the insulator unit or disk next above it. The pin or bolt 6 is embedded in cement within a rooved socket or bore 7 extending up into t e head from below, the bolt projecting beyond or below the plane of the rim of the disk a suflicient distance to make the proper conneetion with the insulator unit next below it. The porcelain disk in the structure shown has a number of integral concentrically depending ribs or petticoats projecting from its under or convex side for the purpose of increasing the surface distance from the cap to the bolt. The bolt of the upper end unit may be formed with an eyelet 8 through which a hooked suspension member 9 may be looped to suspend the entire insulator from the tower arm D. Any suitable method, however, may be employed to suspend the insulator from the tower arm. A depending clampi v member F may be linked to the bolt 0 the lower unit for the purpose of holding the high tension conductor E. The clamp F for this'purpose may be of any suitable or desired design. In this particular case I have illustrated a wire clamp of the type constituting the sub ject matter of my co-pending application, Serial Number 698,419, filed May 20, 1912. In some instances I employ in connection with this clamp a discharge rod G, the major portion of which lies substantially parallel with and immediately above the conductor E. The outer ends Gr however of this discharge member curve or rise upwardly away from the conductor E and project a considerable distance beyond the edge or rim of the insulator disks. As before mentioned I construct the insulator in such manner that the air path is broken down and the fiashover occurs before the insulator becomes punctured by the excessive strains to which it is subjected. I have found by extensive experiments and in practice that by concentrating or localizing the electrostatic tlux or field existing around the insulators when the system is in operation, the air path may be maintained in a partially broken down condition, and when an undue surge or a lightning charge comes on the line, the air path being partially disrupted, readily responds to the abnormal potential and rapidly breaks down completely. In other words the already partially disrupted condition of the air path renders it susceptible to a rapid complete breakdown under less potential than that necessary to puncture concentrate or localize the electrostatic flux or field by placing a flange or rib I-I around the cap 2 of each unit member of the complete insulator. These flanges vary in dimensions and form according to circumstances. They may be in the form of loose metal rings dropped over the caps as shown in Fig. 3 or formed integrally with the cap, (Figs. 1 and 2) the latter being preferable. I have found in actual practice that the most effective results may be obtained by positioning the rib or flange at the base or extreme lower end of the cap close to the upper surface of the porcelain disk. The flange preferably has its outer edge or rim H quite sharp (being rounded but slightly) and in consequence the electrostatic flux or field concentrates and becomes more intense at this flange edge resulting in an intense concentrated direct air path between the rim H at the conductor E or discha-rge tips G as the case may be. There are certain circumstances or conditions under which the discharge might take place from unit to unit instead of from the upper unit to the conductor. An instance of such a condition would be where from some cause one of the units became damaged in such manner that a circuit is established between its metallic parts and those of the unit next adjacent it. If there is .a likelihood of such conditions arising they may be taken care of by adding another similar flange I-I near the top of the cap as shown in Fig. 4. The discharge will then take place between the lower flange of one unit and the upper flange of another unit. ()ne very important but peculiar characteristic which I have found to be inherent in my invention in actual practice is that the potential required to flash over the entire structure directly between the conductor and the cap of the upper unit (which in practice is usually grounded) is always less than the sum of the potentials required to flashover each individual unit. The flange has a flat beveled under surface H reaching substantially to the upper surface of the porcelain and forming in a sense a screen which guards against the short circuiting of the electrostatic streamers over the insulating surface of the disk to the bolt, thus maintaining the potential required to flash over the individual unit as high as if no flange were employed. Another important characteristic is the tendency of the arc to form free of the insulator units so that the heat of the are, particularly of the power are which usually follows, does not fracture or otherwise damage the several parts of the insulator. In Fig. 5 I have illustrated a. slightly different arrangement for concentrating the electrostatic flux; instead of a flange on the cap I provide a series of pyramidic projections P which present a series of rather sharp points around the cap. This arrangement however is probably not as effective as the flange because it does not present a continuous screening undersurface to the electrostatic corona or streamers. The use of the discharge tips C: on the clamp assists to a certain extent in localizing or in tensifyin the flux at a point near the conductors a though these tips are not essential. They do serve to cause the arc to strike at a greater distance from the disks and thereby lessen the danger of cracking the disks from heat.

I claim:

1. The combination of a plurality of insulating units flexibly connected together, each comprising an insulator skirt and a portion oi reduced diameter from which the skirt projects outwardly, and a metallic cap secured over the reduced portion and a projecting flange attached thereto and uniformly surrounding the cap above and in close proximity to the skirt where it joins the said reduced portion.

2. A suspension insulator comprising a plurality of insulating units flexibly connected in series, each having an insulating skirt and a portion of reduced diameter from which the skirt projects outwardly, and a metallic cap secured over the reduced portion with a uniformly projecting and choir cling means attached to the cap and located in close proximity to the skirt where it joins the reduced portion for relieving concentration of electrostatic flux upon the reduced portion and thereby relieving overstress.

3. An insulator of the suspension type comprising a plurality of insulating un'its connected in series, each having an insulating skirt and a portion of reduced diameter from which the skirt projects outwardly and a metallic cap secured over the reduced portion with a uniformly projecting flange attached to and located in close proximity to the skirt at the place where it joins the said reduced portion, and electrical potential conductor at one end of the insulator, and a rounded connection at the other, the said flange relieving the concentrated electrostatic stress upon the reduced portion of each insulator and setting up a partially broken down or ionized condition uniformly around the insulator.

4. A suspension type insulator comprising a plurality of insulating units flexi" bly connected in series, a conductor supported at one end of the insulator and a grounded connection at the other end, each unit having an insulating skirt and a portion of reduced diameter from which the skirt projects outwardly, and a metallic cap secured over the reduced portion with a projecting flange located uniformly about and in close proximity to the skirt where it joins the said reduced portion, the said flanges of the intermediate units operating to concentrate the electrostatic field uniformly about each insulating unit and causing a uniformly ionized condition of the atmosphere surrounding the unit to which said flange is connected so that a flash-over between the ground and the conductor will be led initially and maintainedclear of the intermediate insulating skirts between the conductor and the ground.

5. In an insulator of the suspension type a plurality of insulating units each having a skirt and a portion of reduced diameter from which the skirt projects outwardly and downwardly, a conductor at one end of the insulator, a grounded connection at the other end, and means in connection with each insulator unit projecting uniformly therefrom to relieve the reduced portion from stress tending to puncture it and to set up an ionized condition of the atmosphere entirely surrounding the unit to cause a flash-over to occur between the ground and the conductor clear of the insulating skirt.

6. In combination, an insulator comprising a plurality of insulating units flexibly connected in series, an electrical conductor, means at one end of said insulator for engaging and holdin the conductor in connection therewith, a ar also held in contact with the conductor with extremities extending laterally beyond the insulator units and bent in the direction of the units, a grounded connection at the other end of the insulator, and means in connection with each insulating unit comprising a flanged and pro jecting metal rim which concentrates the electrostatic field about each unit and causes an ionized condition of the atmosphere surrounding the unit so that a flash-over due to increased voltage will occur between the conductor and the ground entirely clear of the insulator units.

7. An insulator adapted to be hung underneath a support and consisting of a plurality of insulating units connected together in series, each unit comprising an insulating member having a reduced portion and an outwardly extending skirt, the reduced portion have a hole closed at one end, a metal cap fitted over and secured to the reduced insulating portion, a metal pin secured 1n and projecting from the hole, means on the cap for attachment to the projecting end of the pin permitting freedom of movement, means surrounding each cap and attached thereto at a point adjacent the insulating skirt for relieving excessive stresses in the 121:)

insulator in case of abnormal rise in voltage, means at one end of the series of insulators for freely suspending the same from a support, and means at the other end of the series of insulators for attachment of a conductor.

8. An insulator to be mounted underneath a support comprising a plurality of flexibly connected insulating members, each having a metal cap secured thereto, means on the cap' for attaching to a support above it to give freedom of movement, a metal pin secured to the insulating member and separated from the cap by the insulating member, means connected to and surrounding the cap at a point adjacent to the insulating member to protect the insulating member from puncture in case of abnormal rise in voltage.

9. In an insulator adapted to be suspended from a support and comprising a plurality of flexibly connected insulating members each having a portion with a reduced diameter and a cavity closed at one end extending into the reduced portion, a metal cap secured thereto, means on the cap for at taching it to a support, a metal pin projecting from and secured within the cavity, and integral means projecting from and uniformly surrounding the cap at a point adjacent to the insulating member to protect it from overstressing and puncture in case of abnormal rise in voltage.

10. The combination of an electrical conductor, an insulator of the suspension type therefor, and means for preventing puncturing and overstressing of the insulators at their weakest points but not preventing fiashover.

11. An insulator of the suspended type comprising a plurality of insulating units each movably connected in series, each unit consisting of two metallic members separated by an insulating member, means connected to one metallic part of each unit and uniformly surrounding the same to uniformly ionize the air surrounding that unit and for giving protection to the insulating member from overstressing, said means consisting of a projecting flange having its lower face projecting outwardly and upwardly and meeting an upper face on the flange, the junction of the two faces forming an edge or blunt apex of an angle.

12. In an insulator adapted to be suspended underneath a supporting arm and comprising a plurality of flexibly connected units each having an insulating member having a portion with a reduced diameter from which a skirt portion extends outwardly, a metal cap fitted over and secured to the reduced portion of the insulating member, a conductor at the lower end of the insulator, a grounded connection at the upper end, and means in connection with each metal cap close to the skirt thereof to set up an ionized condition of the atmosphere surrounding the insulating member to which it is attached to protect the reduced portion of the insulating member from over'stress and puncture and abnormal increased voltage.

13. The conibinationof a number of insulating units flexibly connected in series and composed of a porcelain insulating disk interposed between a metal cap and a metal pin, the lower end of each metal cap being provided with a means for automatically and uniformly ionizing the air surrounding the insulator and the degree of ionization to increase and decrease as the impressed voltage upon each unit increases or decreases;

14. In a suspension type insulator, aplurality of insulatingunits flexibly connected in series each comprising an insulating mem ber having a portion of reduced diameter, and a flanged metal ring connected to and projecting uniformly from the portion of the reduced diameter for preventing puncturing and overstressing of the member at the weakest point thereof but not preventing a flash-over around the several insulating members.

15. A suspension type insulator comprising a plurality of insulating units flexibly connected in series,- each unit comprising two metallic members separated by an insulating member, and one of the metallic members consisting of a cap with a uniform outwardly projecting flange.

16. A suspension type insulator comprising a plurality of separate insulating units flexibly connected in series and each separately rotatable with respect to the other, each insulating unit comprising an insulating member having a reduced portion and an outwardly extending skirt, a pin attached thereto beneath the skirt, and a metallic cap attached to the reduced portion of the member above the skirt and having a uniform outwardly extending flange at the lower edge of the cap adjacent the skirt to set up a uniform ionized condition of the atmosphere surrounding the unit which depends for its strength upon the voltage impressed upon the insulator.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 13" day of May, A. D. 1913.

ARTHUR O. AUSTIN.

Witnesses:

G. V. MARKS, P. S. COREY.

Copies of this patent may be obtained for five c'ents each, by addressing the Commissioner of Patents, Washington, D. G." 

